Organosilicon compositions



United Statesv Patent 3,020,299 ORGANOSILICON COMPOSITIONS JamesMarsden, Schenectady, N.Y., assignor to General Electric Company, acorporation of New York No Drawing. Filed Aug. 15, 1958, Ser. No.755,138- 4 Claims. (Cl. 260-4432) This invention is concerned with novelsilylarylene compositions. More particularly, the invention relates to asilylarylene composition selected from the class consisting of l) acompound having the formula where X is selected from the classconsisting of bromine,

chlorine, and the hydroxyl group, and (2) polymers derived from (1)having the recurring structural unit II 0 CH CH:

Such polymers may have from to 1,000 of such recurring units, inaddition to which the polymer can have terminal silicon-bonded hydroxylgroups.

The monomeric hydrolyzable halogenosilanes described in Formula I abovewere prepared as follows: 280 grams dimethyldichlorosilane, 52.5 gramsmagnesium, and 4000 ml. diethyl ether were placed in a three-neckreaction flask. Thereafter, 200 grams dimethyl-para-dibromophenylsilane[BrC I-I Si(CH C I-I Br] dissolved in 540 ml. ether was added to thestirred reaction mixture over a period of 2.5 hours. The reactionmixture was heated at the reflux temperature of the mass for anadditional 8 hours, and then filtered to remove magnesium halides. Thesolvent and unreacted dimethyldichlorosilane (which was employed inexcess) was removed by distillation at atmospheric pressure. Theresulting mixture (about 233 grams in weight) was distilled at reducedpressure to yield about 85 grams of a solid product boiling within therange of 175 C.-2l0 C. at 0.2 mm. Analysis of this compound showed thatthis product was a mixture of bis(para-dimethyl bromosilylphenyl)dimethylsil-ane and bis(para-dimethyl chlorosilyl phenyl)dimethylsilane (and probably the mixed bromochloro derivative of FormulaI where one X is chlorine and one X is bromine). In this mixture, therewas present about 23 equivalent percent of the bromo derivative andabout 77 equivalent percent of the chloro derivative as evidenced by thefact that analysis for chlorine and silicon of the mixture showed thatthe product contained 13.1% chlorine and 19.6% silicon as contrasted tothe theoretical values of a similar mixture of 13.7% chlorine and 19.5%silicon. By distillation through a more efiicient fractionating column,one can separate the bis-dichloro derivative from the bis-dibromoderivative.

The above-described halosilane product composed of the bromo andchlorosilanes which distilled within the range of 175-2l0 C. at 0.2 mm.was dissolved in 300 ml. diethyl ether and added slowly over a period of2.5 hours with stirring to 1200 ml. of a saturated solution of sodiumbicarbonate and 750 ml. ether. Stirring was then continued for anadditional one hour at room temperature (about 27 C.). The organicsolution was separated and dried with anhydrous sodium carbonate andfiltered. The product of hydrolysis, that is, the silanol, thus obtained was recrystallized from hot toluene, and the white crystalsobtained were found to have a melting point of 126 C. This compound wasanalyzed and found to correspond to Formula I where each X is anhydroxyl group as evidenced by the fact that it was found to have3,020,299 Patented F ch. 6, 1962 ICC 60.4% carbon, 8.2% hydrogen and22.0% silicon as contrasted to the theoretical values for the disilanolof 60.1% carbon, 7.57% hydrogen, and'23.42% silicon. This structure wasalso confirmed by molecular weight determination.

The above prepared disilanol was polymerized with KOH in the presence ofa stream of nitrogen which was passed over the surface of thepolymerizing mass. More particularly about 4.6 ml. of KOH solution(010052 gram KOH per 100 ml. water) was added to 4.6 grams of theabove-described disilanol. The water was removed by heating at about 80C. and passing a stream of nitrogen over the surface of the mixture.After all the water added was removed, the silanol was heated above itsmelting point to cause polymerization. Heating was continued forone-half hour at 0., one hour at 200 C., and 17 hours at ZOO-225 C. Theresulting polymer was a viscous liquid at 150 C. and upon cooling toroom temperature was an elastic solid. This polymer was dissolved inbenzene and washed with water to re move the catalyst. The polymer wasprecipitated from the benzene solution with methyl alcohol. Afterremoval of the solvent by evaporation, the polymer was a clear, elasticsolid. It was comprised of the recurring unit This clear, elastic, solidpolymer can be mixed with fillers such as finely divided silica (e.g.,fume silica, silica aerogel, precipitated silica, etc.) in amountsranging from 0.2 to 2 weight parts of filler per weight part of thesolid polymer, and with small amounts of benzoyl peroxide or otherorganic peroxides capable of effecting cure of the polymer, the amountof peroxide used being within the range of from about 0.1 to 8%, byweight, based on the weight of the solid elastic product. This mixtureof ingredients can be heated at elevated temperatures to about 125 to250 C. for times ranging from '1 to 3 hours to eflect cure andvulcanization of the mixture to the substantially infusible andinsoluble state.

Such organopolysiloxane solids can be employed in various applicationswhere the usual organopolysiloxane rubbers are used. Thus, these curedsolid elastic polymers can be used as gasket materials where it isdesired to have good heat resistance at elevated temperatures and yethave a gasket which is capable of remaining flexible at temperatures aslow as --70 to l00 C. The uncured mixture of the solid elastic polymer,filler, and curing agent can also be dissolved and suspefiled in varioussolvents such as benzene and toluene, and used to coat various cloths,such as glass cloth, to make heat resistant tapes which can be used forinsulation of various electrical apparatus including electric-a1conductors. Alternatively, a copper core can be passed through thesolution-dispersion of the aforesaid elastic polymer, filler and curingagent, and thereafter the coated conducted can be passed into a heatedzone to eifect curing of the insulation to give a heat-resistant outerinsulation for the metallic conductor. The dihalogenosilanes and thedihydroxy derivative of Formula I are useful as intermediates in thepreparation of the polymeric methylpolysiloxanes described in FormulaII. In addition, the halogenosilanes of Formula I can be used to treatvarious solid bodies, such as masonry, textiles, paper, etc., and allowthe treated body to hydrolyze by means of the moisture in the air,thereby to deposit a film on the solid body to render the latterwater-repellent.

The dihydroxy derivatives of Formula I can be inter- 3 4 condensed withother organopolysiloxanes such as cyclic 4. A composition having theformula polysilox-anes (e.g., octamethylcyclotetrasiloxane, octa- CH3CH3 phenylcyclotetrasiloxane, etc.), to give interpolymers havl l ingrecurring units such as Formula II, and in addition, Ho'fihcsmqshcmwshonI dimethylsiloxy and diphenylsiloxy units. 5 CH; Ha CH:

Patent of the United States is:

What I claim as new and desire to secure by Letters Refereuceslcited inthe file of this Patent 1. A composition of matter having the formulaUNITED S TES NTS I 2,352,974 Rochow July 4, 1944 03 CH5 OH: 10 2,507,515Clark May 16, 1950 I l l 2,557,931 Barry June 26, 1951 XAFQHWWWHMPX2,562,000 Sveda July 24, 1951 9 FOREIGN PATENTS 2 i c D where X isselected from the class consisting of bromine, 15 69657 Gram Brmm Sept 21953 chlorine, and the hydroxyl group. OTHER REFERENCES 2.Bis(p-dimethylchlorosilylphenyl)dimethyl silane. Sommer et al.:J.A.C.S., 69, 980 (1947), page 980 re- 3. Bis(p-dimethylbromosilylphenyl) dimethyl silane. lied upon.

UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No.3,020,299 February 6, 1962 James Marsden It is hereby certified thaterIfor appears in the above numbered patent requiring correction andthat the said Letters Patent should read as corrected below.

Column 1, formula (II) should appear as shown below instead of as inthmpatent:

column 3 lines 9 to 13, the formula should appeer as shown below insteadof as in the patent:

CH3 H3 CH3 x-ei-c n -f-ei-c n i--X CH3 I c11 011 Signed and sealed this19th day of June 1962.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents

1. A COMPOSITION OF MATTER HAVING FORMULA FIG -01 WHERE X IS SELECTEDFROM THE CLAS CONSISTING OF BROMINE, CHLORIDE, AND THE HYDROXYL GROUP.